Prevent ts-node being registered twice

Author: apancutt

index.js

@@ -26,11 +26,13 @@ class ServerlessWebpack {
     this.options = options;
 
     if (
-      (_.has(this.serverless, 'service.custom.webpack') &&
-        _.isString(this.serverless.service.custom.webpack) &&
-        _.endsWith(this.serverless.service.custom.webpack, '.ts')) ||
-      (_.has(this.serverless, 'service.custom.webpack.webpackConfig') &&
-        _.endsWith(this.serverless.service.custom.webpack.webpackConfig, '.ts'))
+      (
+        (_.has(this.serverless, 'service.custom.webpack') &&
+          _.isString(this.serverless.service.custom.webpack) &&
+          _.endsWith(this.serverless.service.custom.webpack, '.ts')) ||
+        (_.has(this.serverless, 'service.custom.webpack.webpackConfig') &&
+          _.endsWith(this.serverless.service.custom.webpack.webpackConfig, '.ts'))
+      ) && !process[Symbol.for('ts-node.register.instance')]
     ) {
       try {
         require('ts-node/register');